A hijacked Ethiopian plane that landed at Geneva airport early on Monday (local time) was diverted from Rome by the co-pilot, who sought asylum due to fear of persecution in Ethiopia.

The unnamed co-pilot, an Ethiopian born in 1983, locked the cockpit door when the pilot went to the toilet. He then asked to refuel at Geneva, landed the plane, climbed down from the cockpit window on a rope, and gave himself up to police.

He was unarmed and there was no risk at any time to crew or passengers, police spokesman Pierre Grangean told a news conference.

The co-pilot is being questioned by police.

Earlier, airport police said the passengers and crew were safe, and the situation was "under control" after flight ET 702 had been diverted from its original destination of Rome.

The airline earlier said the flight from the Ethiopian capital Addis Ababa had been ''forced to proceed'' to Geneva.

Police escorted passengers one by one, their hands over their heads, from the taxied plane to waiting vehicles.

In an apparent recording of a radio communication between the aircraft and air traffic control posted on the social media site Twitter, a demand for asylum can clearly be heard.

The authenticity of the recording could not be independently verified and it was not immediately clear whether it was a hijacker or pilot speaking from the plane.

''We need asylum or assurance we will not be transferred to the Ethiopian government,'' the voice in the recording said, posted by Twitter user MatthewKeysLive.

A spokeswoman for the Federal Office of Civil Aviation said Geneva airport had been closed.

Online flight watchers reported picking up a "Squawk 7500" hijack radio code coming from the Ethiopian Airlines flight about 5.30pm, New Zealand time.

Flight ET702 from Addis Ababa to Milan landed in Geneva about 6.15pm (NZT).

The Boeing 767's bizarre flight pattern was plotted live online on flightradar24.com. The site showed the plane making multiple circles around the airport before finally landing.

The airline posted the following statement on its website: "Ethiopian Airlines flight 702 on scheduled service departing from Addis Ababa at 00:30 (local time) scheduled to arrive in Rome at 04:40 (local time) was forced to proceed to Geneva Airport.

"Accordingly, the flight has landed safely at Geneva Airport. All passengers and crew are safe at Geneva Airport.

"Ethiopian Airlines is making immediate arrangements to fly its esteemed customers on-board the flight to their intended destinations."

An Ethiopian Airlines flight between Addis Ababa and Nairobi was hijacked in 1996 by three Ethiopians. The plane crash-landed in the Indian Ocean when it ran out of fuel, killing 125 people, as well as the hijackers.

Ethiopian Airlines is owned by the Ethiopian government and is the fastest growing airline in Africa. In 2012 it became the first African airline to take delivery of a Boeing 787 Dreamliner and has ordered 10 of the cutting-edge new aircraft.

It was established in 1945 and now operates to 86 cities throughout Africa, Europe, Asia and North America.